Citizen vulnerable to stored XSS in sticky header button messages

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2025-62508: 0.45% estimated exploitation activity in the next 30 days; percentile 39.02 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The JS implementation for copying button labels to the sticky header in the Citizen skin unescapes HTML characters, allowing for stored XSS through system messages. Details In the copyButtonAttributes function in stickyHeader.js, when copying the button labels, the innerHTML of the new element is set to the textContent of the old element: https://github.com/StarCitizenTools/mediawiki-skins-Citizen/blob/f4cbcecf5aca0ae69966b23d4983f9cb5033f319/resources/skins.citizen.scripts/stickyHeader.js#L29-L41 This unescapes any escaped HTML characters and causes the contents of the system messages to be interpreted as HTML. PoC 1. Edit any of the affected messages (citizen-share, citizen-view-history, citizen-view-edit, nstab-talk) to the following payload: <img src="" onerror="alert('Sticky Header Button XSS')". 2. Visit any mainpage article in the wiki using the Citizen skin. <img width="495" height="228" alt="image"…

Published by the source

20 Oct 2025, 15:31 UTC

Last modified by the source

20 Oct 2025, 15:31 UTC

Source last checked

26 Oct 2026, 14:34 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-g955-vw6w-v6pp

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# Patch Next advisory brief: CVE-2025-62508

Advisory: Citizen vulnerable to stored XSS in sticky header button messages
IDs: CVE-2025-62508, GHSA-g955-vw6w-v6pp
Record: https://patchnext.com/advisories/cve-2025-62508 (revision 1, source checked 26 Oct 2026, 14:34 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: starcitizentools/citizen-skin 3.9.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist starcitizentools/citizen-skin: affected >= 3.3.0, < 3.9.0; fixed in 3.9.0

## Suggested inspection (read-only)
- Packagist starcitizentools/citizen-skin: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on starcitizentools/citizen-skin.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-g955-vw6w-v6pp (GitHub-reviewed advisory GHSA-g955-vw6w-v6pp lists affected ranges: Packagist starcitizentools/citizen-skin >=3.3.0 <3.9.0)

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